1. Field of the Invention
The present invention relates to a handgrip, having dead-man-switch action, for mounting on the pole or shaft of self-propelled, pole-guided construction equipment, especially pole rollers.
2. Description of the Prior Art
Handgrips of this general type fulfill the function of immediately stopping the construction apparatus when the operator releases the handgrip for any reason, even unintentionally, thus avoiding accidents and injury to persons and/or damage to objects.
The heretofore known handgrips are made in two parts, comprising a stable guide or steering handle and a second, similarly shaped, lighter handle that must be pulled toward the steering handle, against spring force or pivot force, in order to actuate the driving operation and to keep the latter activated. When the two handles are released, the lighter handle either under the effect of gravity or, more likely, via a spring that is generally in the form of a torsion spring, returns to the rest position and frees a spring that was previously tensioned by the actuating lever; this spring severs the driving coupling and activates a brake, so that the roller, etc., is immediately stopped. Handgrips of this type are used not only with purely mechanical rollers, but also with hydrostatically driven rollers.
The heretofore known handgrips are structurally expensive and complex, and are not adequately safeguarded against disconnection of their function, for example by securing the lighter handle to the steering handle. The danger that the dead-man-switch safety action will be circumvented results from the fact that it is somewhat uncomfortable to hold the lighter handle against the force of gravity or spring force for any length of time. Thus if an operator is using the equipment for a long period of time, he can become quite uncomfortable, for example by having his hands cramped, and may be tempted to circumvent the dead-man-switch safeguard, especially since it is so easy to do so.
An object of the present invention therefore is to structurally simplify the handgrip of the aforementioned general type, and moreover to design the handgrip in such a way that on the one hand it is more comfortable for an operator to use, and on the other hand as a dead-man-switch safeguard that cannot be easily deactivated.